Fluid impact pulverizer



March 16, 1954 w VENABLE 2,672,296

FLUID IMPACT PULVERIZER Filed Jan. 4, 1949 5 Sheets-Sheet l 5 Fig.1. 6055 INVENTOR William/Mayo Venab/e March 16, 1954 w. M. VENABLE 2,672,296

FLUID IMPACT PULVERIZER Filed Jan. 4, 1949 5 Sheets-Sheet 2 3% x.INVENTOR MW/amflayo flenab/e 7 gww aw. 0; W

March 16, 1954 w. M. VENABLE FLUID IMPACT PULVERIZER 5 Sheets-Sheet 5Filed Jan. 4, 1949 INVENTOR Mayo V /Iab/e X ofiu, 750x019 541% Wi/UamMarch 16, 1954 w VENABLE 2,672,296

FLUID IMPACT PULVERIZER Filed Jan. 4. 1949 5 Sheets-Sheet 4 INVENTORW/W/am Mayo Vena/e March 16, 1954 w. M. VENABLE FLUID IMPACT PULVERIZER5 Sheets-Sheet 5 Filed Jan. 4, 1949 INVENTOR WIN/am Mayo Venab /e f,0x441 K o. .well;-asi.a-;maximum;ssize desirable;

Patented Mar. 16, I954 NI TE .iijisS Tl"1il? 1- PAT E 70 F F ,1 C 2, f7-2 ,296 FLUID-IMPACT PULVERIZER William 1 Mayo V enable, Pittsburgh,Pa.,1 a s signor, Why mesne assignments, toBla'w-Kno'x Company,

mean ime a we c of De aw :Appliqation-January 4, 1949, Serial No. 69,127

- s glaims; Cla- 241-39) 3 i, This invention relates. 'toxmills of.thetimpact" -cu1tiesare overcome inthe mill of this invention.pulverizer type for-grinding various kindsrof solid In this inventionthe partsv of the apparatus material. Moreparticularly, itirelates .to,;a mill gare so arran ed and 'pr'opor'ti ne a e of iin which streamsofza;gaseousnatmosphere in cientyariety to circulate, the materiallwitha which such material is suspended are directedminimum-expenditure ofpower to separate toward acommon-pointtocause thecomminution coarsermaterial for recirculat on f om fi of such material to desired particlesize. ,terial as adequately as practicable and to' avoid Impactpulverizers.oreatomizers as they are the grindingsofmaterial,excessively beyond a sometimes'called, encompassia numberoftypes minimum size eonsidered mo'st desirable Furancl aroused toogrind-avariety of materials. In 5 in't e mil Of; this invention a id e-general, such pulverizersiproduce fine grinding of of materialsotdiflerent, charactercanibe ground such solid material.by turbulenceinthe. gaseous to predetermined.particle size,,flsuch materialsatmosphere-carrying theiragments of such mawould include solidfuelsvsuchasjcoaland coke terial or by thel'collidingl'actionofthestreams ,i "of-varying degrees of, hardness.- This invention withinthe --apparatus .icarryingizsuch material. 5 is also, applieabletothepulverization oimaterials Thus particlesmaycollide with oneianotherwhen having special; chemical or physical j properties moving inopposite oreconverging directions or ,such-asgrinding abrasives,insecticidepowders,

I may collide:withsomemortionmfatheiapparatusi; paperpulprpowd cata ystf r-hyd c rbon nand thus be: subjectrto fraotureuili'urther, suchversion and many others, ,Other Objects an particles mayimpingeupon-oneganotherv or upon zo vantages of thisinvention will 'beapparent from a portion :of the apparatus wit ig-lancing blows thefollowing description and fromth'e'dra wings,

. and be reducedin size-Joy. attrition. in which,

Inmillsof the type withowhichthisinvention Figure 1. is awerticalview incrosssectiQn f a is --c0ncerned,-th'ese particles. are: entrained in g Imill made in accordance with thi invention, with the gaseousatmospherebyojetsii'onqejectors di 5 its returnpassages removed, and of aseparator rected was to haveaiccmmon intersection. In associatedtherewith;

- order to grindto asufii'cient;degreet-vofirfineness, -Figure 2 isayiewinicross section taken, along the particles are-recirculated tosisuchjets until line II-IIofFigure 1; reduced'to the desireddegreeiaThetgaseous ata Figure 3 is a view in crosstsection taken. alongmosphere is produced and maintainedas the conline H'- i urel and Show nthef eturn sequence of the operation of the jets nwitnsuper-w passages;r heated steam or -compressed airii; .When the Figure 4 is a yerticalviewinrcross section of nature of the material tO b QZ-gIOUIId; requiresit,: I the separator and of a feeding means'for the mill othercompressedgasesimaysbeiusedh:fiIhese gaso1 this inventiontaken at rightangles toithe view eous fluids, inclusive:ofasuchryaporsras;may be;shownin Figure 1;

present, inspirate the particlesi of solidimat erial FigureiA i g ew nro ot eni eken along whichare to be ground andtcausetthem tonbe suslineIVA -IYA of Figure 4; pended in the streams ofigaseousfluid and par-Figure 5 is a. view, taken, along line-W4; of Fig- -tic1es so created. zt r ure 3;

In the pulverizing ofcoal-sornther particles, it ;;wFigure, 6, is, .avertical; view. in cross section of frequently happenssthat particles.whichzhave alanother embodiment ofthis invention;

r ready been ground to the:predetermineddesired 1 -Figure .7 is;a-viewhincross section taken along degree of finenesstremain intheastreams; being line VIL-rYILQf i ure 6; I I

recirculated andz-thusareisubjectgto-unnecessary Figure 8 isaplan viewofone-half.of the emregrinding. with the --coarsers-particlesgwhich are3745' bodimentshown inlifigure 6; and also borne :in the streams, rsincefor/.eachstype 01" 4 Figure 9 is a vertical view incross section takenmaterial it is desirable that thetparticlessbe re along-line IX IX ofFigure 8. duced. only toathat" degree ,of.:-fineneS.S..-Which will ,GReferring to-thegpreierred embodiment shown :exclude =particlesocoarser-thannaw certain size, in Figures; 1; to alaeylindriealcasingfl l1 is00mparticlesi finerethan :thatzcertaincmaximllm $126,150 P d s t t l b11 ine k c q fi ,L e

become, in certainicases,eundesirablesbecause itz -n-zlsqb ply' weldedtogether inlea'ko o is wasteful 10f .ipowen andreduces .zthetcapacityof;

Qasing lll together with bottom ll, and l'a top a .the mill or because:the ;use= ofi;whic;h she ground plate,;de1ine;a:grinding,chamber}l3 "in'which particles are to her-putirenderssaiminimumsize as openings Ithrough each of which a nozzle l6 projects. Each nozzle I5 is held in ablock l1 threadably connected to a plate is which is bolted in sealedengagement with an annular rim l9 welded to casing it around eachopening [5. superheated steam or compressed air is supplied to nozzles[6 through the respective pipes 20. For grinding coal superheated steamis usually supplied to nozzles l5. Nozzles 16 are horizontally directedtoward a common intersection, the point center of which lies on thevertical axis of chamber l3.

Each nozzle [5 is provided with a coaxially positioned barrel 2|pointing toward said common intersection and spaced inadvance of therespective nozzle 16 an amount which provides an annular inlet 22 whichconstitutes the inspiration zone for each jet or ejector comprising anozzle [6 and its attendant barrel 2|. Each barrel 2| is aiiixed andheld in place in the bore of a bracket 23 fastened to bottom l4.Connecting all of the inspiration zones 22 there is a common annularenclosure 24 formed in chamber l3 by an annular top plate 25 and aninner cylindrical wall 25 through which the foreparts of barrels 2!project. In plate 25 there are a series of restricted openings 21corresponding in number to the number of inspiration zones 22 andlocated directly above such zones respectively. Each opening 21 has ascoop 28 associated therewith and adapted to direct particles touchingthe inside of said scoop into and through said opening.

A baffle plate 29 is located in a horizontal plane above the respectivebarrels in spaced relation to said barrels and plate 25 by legs 30. Eachleg 39 is welded or otherwise fastened respectively to a barrel 2! andbaffle plate 29. While baflle plate 29 is a circular disc in theembodiment shown, it may be made rectangular or in any other shape forthe purpose of directing the material that may come in contact with itoutwardly through an annular passage 3| respectivelyjbetween plates 25and 29. This passage 31 must be of suflicient area to permit thepartially ground material to pass through with enough gaseous fluid tocarry it but must not be so large that the fluid flow through passage 3|is too small to retain the larger fragments in suspension. In each case,passage 3! must be designed for the particular kind of material to beground.

A wear plate 32 is afiixed to baffle 29 on the top side thereof in thecenter. This wear plate 32 is adapted to prevent undue wear of bafile29. The material of which wear plate 32 is made may be of a yieldingmaterial to minimize abrasion or of any material suitable for use withthe particular character of the material to be ground. Yet, as are allof the parts of the apparatus, it must also be designed to withstand alltemperatures and other factors which will be encountered in operation.Four curvilinear vanes 33 are set in battle 29 and extend above andbelow the two surfaces thereof. Vanes 33 constitute upstanding anddepending walls running from wear plate 32 to the outer edge of bailie23 in the manner of curved equally spaced spokes on a wheel. Thus, thegaseous streams of gaseous fluid carrying particles of solid material ofdifferent sizes leaving an impact zone 34 generally defined by wall 26,bottom l4 and baffle 29, will be given a rotational or centrifugalmotion by the depending portion of vanes 33 in addition to that alreadyexisting in the chamber as- 2l, where it is held a consequence of theportions of vanes 33 projecting above baffle 23. This rotation in onedirection relative the axis of chamber is imparts to the gaseousatmosphere and suspended particles in the chamber a movement whichcentrifuges the larger of the entrained particles toward the lowerportion of easing iii. In addition-this motion centrifugesthe finermaterial toward the upper portion of casing It and facilitates theremoval of as much thereof as possible from the gaseous fluid which isto be recirculated through barrels 2l. Scoops 28 are inclined in adirection counter to the direction of motion imparted by vanes 33 andthus collect such larger particles for recirculation through inspirationzones 22 and regrinding.

A housing 35 is located in the center of the top of plate 12. Thishousing supports a nozzle block 35 in which a nozzle 31 is threaded.Housing 35 also supports a barrel 38 spaced from nozzle 3'! to providean annular inlet 39 which is the inspiration zone for the feed jet orfeed ejector which comprises nozzle 31 and barrel 38. Gaseous fluid tooperate nozzle 3'! is supplied through a line 48.

Housing 35 has an opening on one side thereof adjacent inspiration zone33, to which opening there is connected a feed conduit 4!, as shownparticularly in Figure 4. A bracket 42 fastened to the edge of plate l2supports conduit M. The outer end of conduit 4! is opened for connectionto a flared hopper 43 to which fresh material is supplied. A screwconveyor 44 is rotatably supported in conduit ll and is turned by asprocket 45 on the shaft thereof for material advancing engagement withthe inside of conduit 4!. Intermediate the ends of conduit 4| in advanceof hopper 43 there is a pipe connection 46 leading to a separator.

An annular hood 41 is centrally supported on the underside of plate l2.This hood includes a frusto-conical recess 43 around the outer portionthereof, the outer peripheral side 49 of which is somewhat longer thanthe inner peripheral side 50. Hood 41 also includes a cylindrical centerportion 5| spaced equally from side 58 and forming an inner annularpassage 52. Center portion 5i is also fastened to the underside of plate12 and extends downwardly a distance substantially equal to the verticalprojection of side 58. Passage 52 is connected through openings in platel2 with four return passage conduits 53 composed of pipe sectionsforming a reentrant loop as shown in Figure 5, connected directly intoauxiliary annular enclosure 24 through the lower section of easing In. Abutterfly damper valve 5 is rotatably supported by a pin 55 in eachconduit 53. The conduits 53 are of relatively large cross-sectionalarea, which area can be efiectively changed to obtain the desiredvelocity of gaseous fluid with such entrained solid material as may betherein to enclosure 24 by adjustment of the setting of damper 54. Insome cases dampers 54 can be entirely closed to achieve particularvelocity conditions through passage 3| and in the remaining portions ofthe apparatus. Two uptakes 56 are connected with chamber 13 throughplate l2 adjacent the uppermost section of casing in. In this positionuptakes 55 are shielded at least partially by side 49 of hood 41. Inaddition, the aggregate cross-sectional area of uptakes 55 issubstantially less than the aggregate crosssectional area of conduits53.

I A separator 51 is joined to the upper ends of 'nection 46.

' ticlesof the :4 land are admi'x'ed'with fresh or untreated maj terialas screw conveyor 4M continues' 'to supply specific combination beencountered and thesize of fS juch particulars constitute'theengineering and-in such'connectionallof the f hiatakestli. espirator-51campusess ranneiiake outerannular passag ifl and a nbe'ntric'mner intoeach "other at'f'th'ir respective-uppei ends throngs an opencurvingaboutfthe 'centra r 'axis" of separato 51 to im'part rotarymotiontothe'st'ream of gaseous --fiuid and entrained-"ground materialrising in passage '58. The" top-"of both" passages is closed 59 belowopening- "60. A bell type spended by' brackets "65 from "the Hence; asthestream passing through opening BB-ground or pulverulent 'material;suspended in the gaseous'ffiuid of the stream and meeting specificationsof predeterf'mined particle sizej-passintoriser' 63* and out of thegrinding mill andseparator. The coarser Fahd heavier ground material inthat stream *moves'downwardly through inner passage 59 and a downcomberV o thereof by a leakproof sleeved! with pipe con- Thus such'co'ar'serand' heavier 'par-- 66 connected-at the lower end groundmaterial pass into conduit the inspiration 'zone' 39" of the feed jet."The 1 portions of the baflie partsincluding the passage 3i and or" theareas ofreturn passages 53, -uptakes .56, the parts of separator 5'! andof the feedingmechanism as well as the restricted-open- "ingsZT and thedimensions ofjchamber l3 will be determined in the light'ofthe-particular qual- 1" ities of the material to be-ground, thenature of the gaseous fluid or fluids usedin the respective jets, thepressures, temperatures and the like to the apparatus. fieldbf processdrawings in this case are to be considered as merely diagrammatic.Moreover, under some conditions, certain kinds of material will notrequire the use of any vanes 33 or such vanes may only be necessary onone side or the other of bafile 29. All portions of the apparatus willalso be suitably insulated where necessary to prevent undue loss ofheat.

An alternative embodiment of this invention is shown in Figures 6 to 9inclusive. Such an alternative embodiment is useful in existing plantsin which the available space is limited especially as to head room. Inthis alternative embodiment, a casing I including a top plate l2 and abottom I 4' define a chamber l3. Except as otherwise noted, the Variousand respective parts of the apparatus in the alternative embodiment arenumbered with the same references primed, as the references used indescribing the preferred embodiment in Figures 1 to inclusive, serve thesame purposes and have the same advantages.

It will be noted that the grinding jets or ejectors comprisin nozzles l6and barrels 2| are and arrangement of uptakes fid'separator 51 andconduit ll are a partgnot of this' invention', but 'ofthe inventionset,iorth iri- United States patent application Serial'No.

69,103, filed on even date herewith, in'the' name wis'e'obstruct thentryof material propelled into 5 impfictzohe ev ct-chamberW"asfqistinsuished '1 amine-preferred embodiment in Wh h themaacme s4.Thefeed jet inthe alterriative embodiand a barrel-38' which'forc'es thematerialintoa doncluitwfiopem f has a Venturi bore 72 in fthe' aiteative-embduias a bailie apartfroin 'baiiieplat fl'. Barrelf'38 "lined:with'refra'ctory blocks 13', a type of provision'whichi'may'also'bem'ade 1 in 'barrel' '38 of'the preferrewe 'nbodimeht. An-

, other purpose isjserved by""theiupw'ard'inclination of nozzle I6" andbarrels2l"in that such positioningfitends 'toinc'rease the pressure ofthe passage 31 therebyassisting in'the'remo'v-alfof. solidi'material,including the feed enteringthroughconduit lll,

outof impact'zone 34. a

. In the alternative embodiment bafileYI'ZQ'j.) is

made with a conicaltop '74 which-producesmovementof any streamdo'wnwardlylimpingmg "thereon toward thefiinnerwalls of casing; 110'.

Rotary. motion isimparted. to the stream flowing out of impact zone 34by curvilinear vanes 33 which also serve to support bafiie plate 29 onthe upward extension ofcircular wall -26".

.Hoodl il' in the alternative embodiment is an annular horizontal plate;having' a central passage 5Z'insteadof arr-annular passage 52as'instruction a. single damperis rigidly afiixed )1 through plate thepreferredembodiment} Becauseof-this conplate -54'- -suffices and is,raised and lowered by a threaded rod 15, having a hand. wheel 16 -at theupper end'thereof,

,and threadably engaging a sleeve 17. "Sleeve 71 to a cupola-78 whichextends 'bywhich a it is supported.

Cupola-18 supports hood 41-- andcyl-indricalwall Return passagegconduits 53'- are" connected Finerigroundmaterial rotatin about theinner -;periphery of casing ID passes out ofcham'ber arrangement throughconduit 10. A suitable separator, not shown, is connected to outlet 56'and the rejected material from that separator may be returned to conduit4| as is done in the preferred embodiment. Brackets 23 support, in thealternative embodiment, the entire grinding jet assembly by being weldedin the corresponding openings in the lowermost section of casing I 0'.Brackets 23 are recessed at 79 to provide the necessary opening betweeneach inspiration zone 22 and auxiliary enclosure 24'.

Although I have illustrated and described but a preferred practice andembodiments of the invention, it will be recognized that changes in theprocedure and structural details may be made covering said impact zone,said baiiie being interposed between said means and said plurality ofjets and defining therewith a velocity exit from said impact zone,curvilinear vanes on said bafile, said vanes curving in one directionand adapted to centrifuge streams of gaseous fluid and particles aroundthe outer portion of said chamber,

a hood centrally located in said chamber above' said baflle, a returnpassage directly connecting said hood and said annular enclosure, and anoutlet adjacent the periphery of said chamber at the top thereof andadapted to be partially shielded by said hood, whereby coarse particlesare carried to said inspiration inlets for grinding in said impact zone,finer particles of not greater than predetermined size are carried outthrough said outlet and gaseous fluid with less entrained materialtherein is circulated through said return passage.

2. Impact apparatus for pulverizing solid fuel, comprising incombination, a chamber, a well defining an impact zone in the lowerportion of said chamber, a plurality of grinding jets directed toward acommon intersection in said impact zone, said grinding jets havinginspiration inlets outside the outer periphery of said wall, an annularplate defining with said wall an annular enclosure for said inspirationinlets, means for feeding solid material borne in gaseous fluid intosaid chamber adjacent said impact zone, a baflle above said commonintersection and between the same and said means, said baflie beingspaced from and substantially covering said impact zone to define withsaid wall an annular exit therefrom, means adjacent said annular exitfor imparting rotational force to streams of gaseous fluid and particlesexiting from said impact zone, an outlet for particles of sufficientfineness adjacent the periphery of said chamber in the upper portionthereof, and a return outlet nearer the vertical *3 8 axis of saidchamber for returning gaseous fluid to saidannular enclosure around theoutside of said chamber.

3. Apparatus for pulverizing solid material, comprising in combination,a closed chamber, a generally vertical wall adjacent the bottom of saidchamber and surrounding an unobstructed impact zone therein, a pluralityof ejectors for grinding and recirculating material to be ground withinsaid chamber, said ejectors being generally horizontal and directedtoward a, common intersection within said impact zone, said ejectorshaving nozzles and barrels, said barrels extending through openings insaid wall, the inlets to said barrels being outside said wall in anauxiliary annular enclosure, an annular plate covering the top of saidenclosure and having restricted openings therein, a baiiie plate closelyspaced relative to the upper edge of said wall to provide therewith anannular outlet passage from said impact zone into the remainder of saidchamber, said annular outlet passage being adjacent said restrictedopenings, radially oiiset vanes adjacent said annular outlet passage toimpart rotational force in one direction to streams of gaseous fluid andsolid particles leaving said impact zone, scoops adjacent saidrestricted openings extending in a direction opposed to the direction ofrotation imparted by said vanes, means for feeding a stream of gaseousfluid material to be ground into said chamber adjacent said impact zone,and an outlet pipe connected to the upper outer portion of said chamberto remove gaseous fluid suspended particles of ground materialtherethrough.

WILLIAM MAYO VENABLE.

References Cited in the file of this patent UNITED STATES PATENTS

